The objective is to determine the factors regulating fetal and maternal cortisol production in primate pregnancy. Current areas of investigation using the baboon as a model, include: 1) examination of fetal cortisol production and secretion in vivo and its relationship to the enzymatic-maturational changes occurring in the fetal adrenal during gestation; 2) examination of the role of cortisone, which we have established is secreted by the neonatal baboon adrenal, as a potential cortisol precursor; 3) determination of the trophic factors regulating neonatal adrenal cortisol production in vivo; 4) determination of the extent to which adrenal de novo precursors and placental precursors are utilized by the baboon fetal adrenal for cortisol production; 5) identification of urinary cortisol metabolites peculiar to pregnant and newborn baboons; 6) determination of the importance of protein binding and metabolism on the rate of clearance of cortisol. BIBLIOGRAPHIC REFERENCES: Epstein, M. F., Farrell, P. M., Sparks, J. W., Pepe, G. J., Driscoll, S. G., and Chez, R. A.: Maternal Betamethasone and Fetal Growth and Development in the Monkey. Am. J. Ob. Gyn. 127: 261-263, 1977. Pepe, G. J., and Townsley, J. D.: Catabolic Regulation of Blood Cortisol in Premature and Term Baboon Neonates. J. Steroid Biochem, 1977 (In Press).